HARTFORD, Conn. - A 17-year-old girl with cancer and her mother are battling Connecticut over an order that she accept chemotherapy treatments - and the state's Supreme Court has agreed to an expedited ruling in a rare case involving the "mature minor doctrine."

HARTFORD, Conn. — A 17-year-old girl with cancer and her mother are battling Connecticut over an order that she accept chemotherapy treatments — and the state’s Supreme Court has agreed to an expedited ruling in a rare case involving the “mature minor doctrine.”

Lawyers for Cassandra C. argue that she is mature enough to make the decision to reject the treatments, but the state Department of Children and Families, or DCF, is saying the treatments are in her best interest.

“Everyone agrees it’s a serious illness, but you’re talking about a fundamental question: Does she have a say in what happens to her body?” said attorney Michael Taylor of West Hartford, who represents Cassandra’s mother.

Cassandra was diagnosed with Hodgkin’s lymphoma in September, according to a state Judicial Branch summary of the case.

The summary notes that “while the recommended treatment for the disease includes chemotherapy, Cassandra decided that she did not want to undergo treatment, and Cassandra’s mother supports her in that decision.”

At a hearing in November, a Superior Court judge granted a request from DCF to take temporary custody of Cassandra “and ordered her mother to provide and cooperate with medical care under DCF’s supervision and as recommended by her doctors,” the case summary states.

Cassandra and her mother initially complied with the court order, and the teenager received her first two chemotherapy treatments in November. But Cassandra “subsequently ran away from home to avoid further treatment,” the summary said. When she returned, she continued to refuse the treatment.

Cassandra now is in an unidentified local hospital receiving treatment under the court order. Details about her prognosis were not available.

Arguments before the state Supreme Court are set for Thursday.

At age 18, Cassandra and her family would have had considerably more control over her medical decision-making. But lawyers for the mother and teen argue that the state should recognize the “ mature minor doctrine,” which holds that some minors possess the maturity to make their own medical decisions, even if younger than the age of majority.

Taylor said “family integrity” — the right for a family to make educational, moral and other major decisions without state interference — also is a major element in this case.

As of 2013, 17 states — but not Connecticut — allowed some form of the mature minor doctrine, according to an article in the journal Pediatrics. But those laws generally grant minors the ability to consent to medical treatment against the wishes of their parents, while Cassandra’s case is seeking legal authority as a minor to refuse treatment.